Never before have we had so much information at our fingertips. You might think that we are better-informed than ever, but there's one thing we can't ask Google: 'What should I be googling?' The way we consume information in the digital age has been blamed for driving political polarisation and leaving us unable to agree on basic facts. It's also making us stupider. Personalised news feeds and social media echo chambers narrow our potential knowledge base. By now, we don't even know what we don't know. In Head in the Cloud, William Poundstone investigates the true worth of knowledge. An entertaining manifesto underpinned by big data analysis and illustrated by eye-opening anecdotes, it reveals the surprising benefits of broadening your horizons and provides an unnerving look at the consequences of being ill-informed.